Transesophageal monitoring of aortic blood flow during nonemergent canine surgeries

Abstract

Objective: To establish baseline values for descending thoracic aortic blood flow parameters as determined with a transesophageal combined M-mode and pulsed Doppler ultrasound-based monitoring method. Design: Preliminary observational study. Setting: University small animal teaching hospital. Animals: The study population consisted of anesthetized canine patients undergoing nonemergent surgeries. Prospectively set criteria for inclusion were adequate body size for placement of the esophageal probe and a nonemergent reason for surgery. The criterion for exclusion was recent trauma. Interventions: Placement of the transesophageal probe. Measurements and main results: Data was collected during 15 surgeries. Data from three dogs was excluded from data analysis (two recently hit by motor vehicles, one recently having undergone a total hip replacement). Each parameter was stable across time within each individual dog. The ranges of the descending thoracic aortic parameters across the 12 nonemergent cases were as follows: Blood flow, 0.038–0.085 L min −1 kg −1 ; blood flow per beat, 0.31–0.84 mL kg −1 ; blood acceleration, 6–29 m s 2−1 ; blood peak velocity, 38–105 m s −1 ; left ventricular ejection time interval 331–492 ms; and diameter, 0.30–0.93 mm kg −1 . Conclusions: The range of descending thoracic aortic blood flow parameters encountered in this small group of dogs during nonemergent surgeries was broad; however, each parameter was quite stable across time with little change occurring in any dog during monitoring. © Veterinary Emergency and Critical Care Society 2002.